T lymphocytes in patients with Down's syndrome

Area of Science:

• Immunology
• Genetics
• Clinical Medicine

Background:

• Down syndrome (DS) is associated with immune system abnormalities, increasing susceptibility to infections and malignancies.
• Previous studies suggest potential immune dysregulation in individuals with DS.

Purpose of the Study:

• To quantify T lymphocyte numbers and assess T cell function in institutionalized individuals with Down syndrome.
• To investigate potential correlations between T cell abnormalities and infection/malignancy risks in DS.

Main Methods:

• Peripheral blood T lymphocytes were quantified in 82 institutionalized patients (50 DS, 27 controls).
• Included comparative analysis of circulating T cell numbers, "avid" T cells, and blastogenic response to mitogens.
• Patient groups included controls, chronic lymphocytic leukemia, acute leukemia, and Hodgkin's disease.

Main Results:

• Circulating T cell numbers in DS patients were within normal limits and not significantly different from controls.
• "Avid" T cell counts were significantly elevated in DS patients compared to controls.
• The blastogenic response of T cells to mitogens was significantly depressed in DS patients.

Conclusions:

• While total T cell numbers are normal, DS patients exhibit altered T cell populations and function, indicated by increased "avid" T cells and reduced mitogen response.
• These findings suggest qualitative immune abnormalities in Down syndrome.
• Infection proneness in DS patients over 15 years old was not higher than other institutionalized individuals, except for those with congenital heart disease.